1. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments The Square Kilometer Array: Introduction and Current Developments Jim Cordes, Cornell University The SKA Project SKA science case Fundamental questions in physics, astrophysics and astrobiology Unprecedented capacity for discovery International and US activity Issues Siting Finance Phased deployment Rescoping  20  50

2. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments SKA: What is It? An array telescope that combines complete sampling of the time, frequency and spatial domains with a  20 to 50 increase in collecting area (~ 1 km 2 ) over existing telescopes. Frequency range 0.1 – 25 GHz (nominal) Limited gains from reducing receiver noise or increasing bandwidth on current arrays Innovative design needed to reduce cost 10 6 meter 2  ~ €1,000 per meter 2 c.f. existing arrays ~ €10,000 per meter 2 An international project from the start International funding Cost goal ~ € 1 billion 17-country international consortium Executive, engineering, science, siting, simulation groups Timeline for construction extends to 2020 Can be phased for different frequency ranges Can do science as you build (“go as you grow”)  20  50

3. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments Science with the Square Kilometer Array edited by Chris Carilli Steve Rawlings Special issue of New Astronomy Reviews Volume 48, December 2004, 979-1605 (48 chapters) Five key science projects Discovery science Enabling understanding in fundamental physics and origins

4. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments Five Key Science Areas for the SKA TopicGoals Probing the Dark Ages 1. Map out structure formation using HI from the era of reionization (6 < z < 13) 2. Probe early star formation using high-z CO 3. Detect the first active galactic nuclei Gravity: Pulsars & Black Holes 1. Precision timing of pulsars to test theories of gravity approaching the strong-field limit (NS-NS, NS-BH binaries, incl Sgr A*) 2. Millisecond pulsar timing array for detecting long-wavelength gravitational waves Cosmic Structure 1. Understand dark energy [e.g. eqn. of state; W(z)] 2. Understand structure formation and galaxy evolution 3. Map and understand dark matter Cosmic Magnetism Determine the structure and origins of cosmic magnetic fields (in galaxies and in the intergalactic medium) vs. redshift z The Cradle of Life 1. Understand the formation of Earth-like planets 2. Understand the chemistry of organic molecules and their roles in planet formation and generation of life 3. Detect signals from ET

5. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments Was Einstein Right About Gravity? The SKA as a Pulsar/Gravity Machine Relativistic binaries (NS-NS, NS-BH) for probing strong-field gravity Orbit evolution + propagation effects of pulsars near Sgr A* Millisecond pulsars < 1.5 ms (EOS) MSPs suitable for gravitational wave detection 100s of NS masses (vs. evolutionary path, EOS, etc) Galactic tomography of electron density and magnetic field; definition of Milky Way’s spiral structure Target classes for multiwavelength and non-EM studies (future gamma-ray missions, gravitational wave detectors) Blue points: SKA simulation Black points: known pulsars Millisecond Pulsars Relativistic Binaries Today Future SKA SKA only 6! ~10 4 pulsar detections

6. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments Flowdown from SKA Science to Technical Requirements TopicType of Obs. Freq. (GHz) Baselines Special Requirements Dark Energy & Cosmic Structure M * galaxies at z=20.3 – 1.4300 Large FOV for survey speed Gravity: Pulsars & Black Holes Full Galactic Census Precision Timing Extragalactic pulsars 0.5 – 15 GHz Core < few km Extended >3000 km Full SKA for extragalactic; Full FOV fast sampling Probing the Dark Ages HI structure 6 < z < 13 CO at z>6 The first AGNs 0.1 - 20100 to > 3000 to 35 GHz for CO Cosmic Magnetism Faraday rotation of 10 8 extragalactic sources 0.3 - 10300 -40dB polarization purity The Cradle of Life protoplanetary disks SETI >20 0.5-11 > 3000Multiple beams

7. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments SKA Frequencies and Technologies

8. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments Surveys: past, present and future

9. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments The Collecting Area Plateau in Radio Astronomy Recent growth in sensitivity has exploited low-noise devices, developments in digital signal processing bandwidth, and calibration and imaging techniques. Increased collecting area enables: Detection of L* galaxies in HI at z ~2 Epoch of Reionization analysis GRB afterglows  100 fainter than currently Detection/timing of pulsars near Sgr A* Gap structure in young, protoplanetary disks

10. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments The 6 th Key Science Area: Exploration of the Unknown Today’s hot new issues are tomorrow’s old issues. The excitement of the SKA will not be just the old questions it will answer but in the new questions it will raise. We build telescopes for … discovery and understanding. What is the right mix? Entirely new classes of objects and phenomena will be discovered if the SKA has appropriate flexibility in its operations (digital signal processing capabilities, array configuration, field of view, etc.) c.f. Exploration of the Unknown, Wilkinson et al. in SKA science book

11. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments DiscoveryDateEnabled byTelescope Cosmic radio emission1933 Bruce Array (Jansky) Non-thermal radio emission1940 Reber antenna Solar radio bursts1942,  t Radar antennas Extragalactic radio sources1949  Australia cliff interferometer 21 cm line of hydrogen1951 theory,  Harvard horn antenna Mercury and Venus spin rates1962, 1965RadarArecibo Quasars1962  Parkes occultation Cosmic Microwave Background1963  S, calibration Bell Labs horn Confirmation of General Rel.1964, 1970s theory, radar,  t,  Arecibo, Goldstone, VLA,VLBI Cosmic masers1965  UC Berkeley, Haystack Pulsars1967 ,  t Cambridge 1.8 hectare array Superluminal motions in AGNs1970  Haystack-Goldstone VLBI Intersteller molecules and GMCs1970s theory,,  NRAO 36ft Binary neutron stars and gwaves1974-present ,  t Arecibo Gravitational lenses1979 theory,  Jodrell Bank interferometer First extrasolar planet system1991 ,  t Arecibo Size of GRB fireball1997,  S, theory VLA Key Discoveries that Illustrate Discovery Space in Radio Astronomy

12. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments DiscoveryDateEnabled byTelescope Cosmic radio emission1933 Bruce Array (Jansky) Non-thermal radio emission1940 Reber antenna Solar radio bursts1942,  t Radar antennas Extragalactic radio sources1949  Australia cliff interferometer 21 cm line of hydrogen1951 theory,  Harvard horn antenna Mercury and Venus spin rates1962, 1965RadarArecibo Quasars1962  Parkes occultation Cosmic Microwave Background1963  S, calibration Bell Labs horn Confirmation of General Rel.1964, 1970s theory, radar,  t,  Arecibo, Goldstone, VLA,VLBI Cosmic masers1965  UC Berkeley, Haystack Pulsars1967 ,  t Cambridge 1.8 hectare array Superluminal motions in AGNs1970  Haystack-Goldstone VLBI Intersteller molecules and GMCs1970s theory,,  NRAO 36ft Binary neutron stars and gwaves1974-present ,  t Arecibo Gravitational lenses1979 theory,  Jodrell Bank interferometer First extrasolar planet system1991 ,  t Arecibo Size of GRB fireball1997,  S, theory VLA from the Discovery Space in Radio Astronomy Nobel Prizes from the Discovery Space in Radio Astronomy

13. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments ,, t, pol , ,  t Large processing FOV High sensitivity : Combine Greater Sensitivity with Wide Field of View Processing The SKA combines a >  20 boost in sensitivity with unprecedented utilization of the field of view

14. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments The International SKA Project International SKA Project Office (ISPO) Richard Schilizzi (Director) Peter Hall (Project Engineer) Project Scientist (TBD) Is conducting site testing in advance of site selection International SKA Steering Committee (ISSC) 21 total members (7 Europe, 7 US, & rest of the world) Working groups: Science, Simulations, Site Evaluation, Engineering, Operations, Outreach Advisory Committees (Science, Site Selection, …)

15. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments

16. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments Siting the SKA Current siting “decision” is late 2006 (ISPO) Argentina, Australia, China, South Africa: proposals expected by end of 2005 Working plan: single site for all frequencies, covered with 2 to 3 antenna technologies (subject to optimization vs. cost/performance) Dipoles ≤ 0.3 GHz Aperture array or dishes0.3 ≤ ≤ 2 GHz Paraboloids ~ 1 ≤ ≤ 25 GHz US perspective: good to explore alternatives to a single-site SKA low-frequency array in southern hemisphere »radio quiet zone » ≤ 2 GHz SKA high-frequency array built upon the EVLA+VLBA ?? »Better tropospheric properties than some southern sites, RFI less an issue »leverages existing investments »recognizes international utilization of EVLA, VLBA Proposed by the US SKA Consortium to the International SKA Steering Committee as a Discussion Document (2005 April)

17. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments Discussion Issues Design and usage issues for the SKA Phased deployment of the SKA vs. frequency? Tradeoffs between science goals and cost? Size of core array usable for searching? Polarization calibration across wide FOV How to deal with the huge number of new pulsars: –Time only the best after initial quick assessment? –Require multibeam capability?

18. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments Discussion Issues Astropolitics: SKA science case needs continual promotion Need to jointly promote gravity studies: –Laboratory and spacecraft gravitational wave detectors –Pulsars as clocks and gravitational laboratories Sometimes perceived as having no connection and/or in competition Joint SKA and LISA meeting?

19. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments SKA Development in the US US Concept: Large-N/Small-D (LNSD) The US SKA Consortium prepares whitepapers on the LNSD concept for consideration by the International SKA Steering Committee and also for a SW US high-frequency SKA site Allen Telescope Array Low-frequency arrays (MWA, LWA) = science and technology precursors Deep Space Network Array: closely related to US SKA concept, strong possibilities for economies of scale Explicit SKA development: NSF ATI Grant: ($1.5M) 2002-2005 Technology Development Project (TDP) »$32M over 5 years (NSF proposal pending) »End to end development, costing, preliminary design »Organized through the US SKA Consortium (17 institutions) »Managed by NAIC/Cornell »Facilitates and unifies SKA development at NRAO, NAIC, and institutions involved with low-frequency array development The next steps await outcome of the NSF’s “Senior Review” (Spring 2006)

20. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments Further The SKA is still TBD with respect to design, science emphasis, feasibility, funding The SKA is in fierce competition for funding all around the world We need to promote the pulsar/gravity KSP as strongly as possible The KSPs are not frozen categories: creatively enhance or supplant them!

21. 16 Aug 2005Jim Cordes: SKA: Introduction and Current Developments